US3812499A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical exposure time control device for use in a photographic camera
Assignee: Minolta Co Ltd
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Filing: 1973-08-02
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Granted: 1974-05-21
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Expires: 1993-08-02
Abstract
Abstract A camera includes a shutter whose closing is actuated by an electromagnet controlled by an electrical timing circuit which is provided with a photosensitive element and a circuit disabling switch. A pair of accessible coupling terminals are connected to the opposite ends of the electromagnet. An accessory is separably mounted on the camera and includes a photosensitive element controlled timing network having an output provided with a pair of coupling terminals which separably engage the electromagnet terminals and the disabling switch may be manually opened or is opened automatically with the coupling of the terminals. More than one shutter control accessory may be provided and the timing circuits may be of different types, with different fields of light responsiveness and with manually selectively adjustable timing intervals.
Inventors
- 👤 T Hayashi
- 👤 A Yoshizaki
- 👤 K Tsujimoto
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 06:57
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083; G03B9/00; G03B9/58
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
91 words
An electrical exposure time control device for use in a photographic camera, comprising: a camera body including a shutter, an electromagnet controlling the closing of said shutter and a pair of connecting terminals connected to the terminals of said electromagnet; an accessory separably mounted to said camera body and including an electrical exposure time control circuit and a pair of connecting terminals engagable with the output of said exposure time control circuit; and means for separably coupling the connecting terminals of said accessory to the connecting terminals of said camera body.
Claim 2
Dependent Claim
91 words
An electrical exposure time control device for use in a photographic camera, comprising: a camera body including a shutter, an electromagnet controlling the closing of said shutter and a pair of connecting terminals connected to the terminals of said electromagnet; an accessory separably mounted to said camera body and including an electrical exposure time control circuit and a pair of connecting terminals engagable with the output of said exposure time control circuit; and means for separably coupling the connecting terminals of said accessory to the connecting terminals of said camera body.
Claim 3
Dependent Claim
44 words
An electrical exposure time control device for use in a photographic camera as set forth in claim 1, wherein said camera further comprises: an exposure time control circuit and switch means for interrupting the actuation of the electromagnet by said exposure time control circuit.
Claim 4
Dependent Claim
52 words
An electrical exposure time control device for use in a photographic camera as set forth in claim 2, wherein said switch means is normally closed to actuate said exposure time control circuit, and means responsive to the coupling of said accessory terminals to said camera body terminals for opening said switch means.
Claim 5
Dependent Claim
63 words
An electrical exposure time control device as set forth in claim 2, wherein one of the exposure time control circuits includes a light receiving element exposable to the light from the entire scene to be photographed and the other exposure time control circuit includes a light receiving element exposable to the light from a specific limited area in the scene to be photographed.
Claim 6
Dependent Claim
43 words
An electrical exposure time control device as set forth in claim 1, wherein said camera body is a single lens reflex camera body provided with a focussing screen and said accessory is provided with a pentagonal prism removably mounted on said focussing screen.
Claim 7
Dependent Claim
144 words
An electrical exposure time control device as set forth in claim 5, wherein said single lens reflex camera comprises an exposure time control circuit and switch means for interrupting the actuation of said electromagnet by means of said exposure time control circuit; one of said exposure time control circuits includes a light receiving element which is exposable to light not traversing the objective lens mounted on said camera body, the other exposure time control circuit includes a light receiving element exposable to light traversing said objective lens and storage means for storing a voltage responsive to the light incident on said respective light receiving element, a timing circuit adapted to produce an output in response to the stored voltage in said storage means, a switching circuit responsive to the output from said timing circuit, and electrical couplings connecting said output to said electromagnet terminals.
Claim 8
Dependent Claim
99 words
An electrical exposure time control device as set forth in claim 6, wherein said pair of connecting terminals connected to the opposite terminals of said electromagnet consist of a pair of contact pieces; and wherein said connecting terminals, connected to the output terminals of said switching circuit in said accessory provided with a pentaGonal prism, have contact pieces engaging said pair of contact pieces, when said housing is mounted on said focussing screen of said camera body; whereby said switch means may interrupt the actuation of said electromagnet by the exposure time control circuit incorporated in said camera body.
Claim 9
Dependent Claim
115 words
An electrical exposure time control device for use in a photographic camera, comprising: a camera body provided with at least a shutter, an electromagnet operable to control the closing of said shutter and pairs of connecting terminals connected to the respective opposite ends of said electromagnet; a plurality of accessories mountable on said camera body and having an exposure time control circuit for electrically controlling the exposure time and a pair of terminals connected to the output thereof; and means for selectively connecting the connecting terminals of said camera body to the connecting terminals of the exposure time control circuit incorporated in a selected one of said plurality of accessories mounted on said camera body.
Claim 10
Dependent Claim
115 words
An electrical exposure time control device for use in a photographic camera, comprising: a camera body provided with at least a shutter, an electromagnet operable to control the closing of said shutter and pairs of connecting terminals connected to the respective opposite ends of said electromagnet; a plurality of accessories mountable on said camera body and having an exposure time control circuit for electrically controlling the exposure time and a pair of terminals connected to the output thereof; and means for selectively connecting the connecting terminals of said camera body to the connecting terminals of the exposure time control circuit incorporated in a selected one of said plurality of accessories mounted on said camera body.
Claim 11
Dependent Claim
79 words
An electrical exposure time control device as set forth in claim 8, including an exposure time control circuit in said camera body and wherein said selectively connecting means includes normally closed switch means for actuating said exposure time control circuit incorporated in said camera body, and including means for opening said switch means in response to the connecting terminals of at least one of said plurality of accessories being connected to a pair of opposite terminals of said electromagnet.
Claim 12
Dependent Claim
52 words
An electrical exposure time control device as set forth in claim 8, wherein said camera body is a single lens reflex camera body provided with a focussing screen and wherein one of said plurality of accessories includes a housing provided with a pentagonal prism and is removably mounted on said focussing screen.
Claim 13
Dependent Claim
195 words
An electrical exposure time control device as set forth in claim 10, wherein said plurality of accessories are provided with a pentagonal prism and include: a first accessory comprising a housing enclosing a first exposure time control circuit and a first coupling member with connecting terminals; a second accessory comprising a second exposure time control circuit and a second coupling member with connecting terminals, one of said first and second exposure time control circuits and the third exposure time control circuit incorporated in said camera body having a light receiving element positioned to receive the light from the entire scene to be photographed not traversing the camera objective lens mounted on said camera body, another circuit being provided with a light receiving element disposed to receive light from a specific area in the object scene, and a further circuit being provided with a light receiving element positioned to receive the light traversing the objective lens from the scene, storage means for storing a voltage responsive to the light incident on said light receiving element of said further circuit, a timing circuit responsive to said stored voltage, and a switching circuit responsive to said timing circuit.
Claim 14
Dependent Claim
116 words
An electrical exposure time control device as set forth in claim 10, wherein at least one pair of a plurality of connecting terminals which are connected to the opposite ends of said electromagnet consist of a pair of contact pieces and wherein the first connecting terminals, which are connected to the output terminals of a first accessory exposure time control circuit consist of a pair of contact pieces separably engageable with a pair of contact pieces of said electromagnet, said selective connecting means including switch menas for interrupting the actuation of the electromagnet by the exposure time control circuit incorporated in said camera body, when said both pairs of contacting pieces are connected to each other.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-05-20 | 1977-11-19 | 1978-05-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-05-20 | 1981-11-19 | 1982-05-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-05-20 | 1985-11-19 | 1986-05-21 | $7700.00 | Window Closed / Lapsed |